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火星上曾存在水--04年科学最大突破
http://www.sina.com.cn 2004/12/20 10:52  国际在线

  The discovery of water on Mars was the scientific breakthrough of 2004, according to one of the world's leading science journals. The water was saline, acidic - and capable of supporting life.

  A spacecraft called Stardust sailed through the coma of a comet on the far side of the sun, and a joint Nasa-European mission sped through the rings of Saturn on the way to a landing on Titan, biggest moon in the solar system, in January.

  But the big prize of the year, in Science's estimation, went to two robots that confirmed that water had once washed over the surface of Mars. The two US six-wheeled robot geologists called Spirit and Opportunity touched down on the red planet in January on what was to have been a three-month mission, covering perhaps a kilometre of Martian surface between them.

  Eleven months later, and with almost six kilometres on the clock between them, the explorers are still at work in the icy grip of the Martian winter.

  The two automatons, equipped with mobile arms and stereoscopic cameras at eye-level height, are a rehearsal for yet more robotic explorations. "With humans on Mars a distant prospect, the robots alone will be striving for the next Breakthrough of the Year on the Red Planet," the US journal Science reports today.

  Their success has been both a delight and a goad to British scientists, who dropped Beagle 2, their own Martian lander, on Mars on Christmas Day 2003 - and then heard nothing. The two Mars rovers were designed to look for evidence of liquid water, without which life would be impossible. But Beagle 2 carried sophisticated equipment that might have been able to detect the chemical signatures of life itself. Anxious scientists waited for weeks, hoping that Beagle would send a message home.

  Almost half of all missions to Mars in the last 40 years have ended in failure. The US space agency Nasa lost four consecutive probes in one 15-month period in 1998-99. But the stakes are high: the red planet remains the most likely place beyond Earth to have ever supported life.

  The race is on. A Nasa lander will touch down on the Martian polar ice sheet in 2008. The Americans hope to send a robot mobile laboratory to Mars in 2009. In the longer term, European scientists are contemplating a robot mission that will land on Mars, collect a scoop of Martian rock and bring it back to Earth. And both Nasa and the Europeans are considering - 20 years from now - a human mission of exploration.

  The other nine: From hobbits to the reshaping of chemistry

  The littlest humans

  The startling discovery of the bones of a small species of human, Homo floresiensis, that stalked the Indonesian island of Flores 18,000 years ago.

  Condensates

  Researchers learned more about the fifth state of matter, the Bose-Einstein condensate. At ultra-low temperatures, atoms in the condensate behave as one. Genome gem

  "Junk" DNA

  Stretches of "junk" DNA between human genes have turned out to be essential for helping genes turn on and off at the right time, and in the right part of the body.

  Goodbye, life

  Rigorous studies confirmed that many plants, amphibians, birds and butterflies face extinction, under pressure from human expansion and climate change.

  Private-public partners

  2005 was the year in which big business, rich foundations, academics and campaigners united in the search for malarial vaccine trials and anti-HIV drugs

  Wet genes

  Scientists sampled water from old mines and found lengths of DNA - a technique that could help identify life too small or remote to observe directly.

  Pulsar pair

  Astrophysicists found the first pulsars - huge spinning neutron stars locked in mutual orbit - and hope to learn more on Einstein's theory of general relativity

  Cloned human embryo

  South Koreans used 242 eggs from 16 volunteers to create a brief-lived clone to demonstrate the possibility of a supply of embryonic stem cells for use in medicine.

  More water

  A flurry of papers threw new light on the nature of the universal solvent, and the discoveries could reshape both chemistry and the atmospheric sciences.

火星上曾存在水--04年科学最大突破

  据最新一期美国《科学》杂志报道,“有确凿证据显示,火星上曾存在着蕴育生命的水”这一发现,堪称2004年世界科技领域的最大突破。

  在2004年,两个人造“功臣”——机器人“勇气号”和“机遇号”在火星上取得了令人欣喜的发现:它们发现了“不容置辩的证据”,证实火星表面上曾经存在着可以蕴育生命的水。由美国制造的“勇气号”和“机遇号”于今年1月到达火星,原定进行为期3个月的考察。不过,11个月已经过去了,这两个机器人依然在寒冷的火星上工作着。

  最近40年来,人类大部分探索火星的尝试都以失败告终。美国航空航天局在1998年和1999年间的15个月内接连损失了4个机器人;而2003年圣诞节当天,由英国发射的火星探测车“猎兔犬二号”在登陆火星之后至今“生死未卜”。最可惜的是,与“勇气号”和“机遇号”两个机器人装备的机械手臂和实体镜照相机相比,“猎兔犬二号”上所携带的仪器要先进、完善得多。如果不是因为发生意外,“猎兔犬二号”的高科技装备有可能直接探测出火星上生命物质发出的化学信号。

  尽管如此,科学家们依然对火星探索情有独钟——毕竟这颗红色的星球是除了地球之外,最有可能存在过生命的星球。如今,“火星上存在水”的这一发现引发了科学家们对地球以外这颗更小、更寒冷的“邻居”更大的探索热情。欧洲的科学家们正在计划重返火星,“猎兔犬二号”的制造者科林·皮林格已经开始着手设计“猎兔犬三号”了;而美国航空航天局也计划在2008年发射一颗火星登陆车,对火星极地的冰层进行探索;2009年,美国还计划将一个机器人活动实验室送到火星上。无论是欧洲还是美国,科学家们不约而同的将今后的20年视为人类探索火星的重要阶段。

  除此之外,《科学》杂志还评选出了其他9项2004年度科学突破:

  第2大突破

  科学家在印尼弗洛里斯岛发现了小矮人的骸骨,这种名为“哈比人”的小矮人又被称为“Homo Floresiensis”(弗洛里斯的人类),生活在1.8万年前。这个惊人的发现是1个世纪以来人类学的最大突破,改写了人类进化的历史。

  第3大突破

  韩国科学家克隆人类胚胎。这项工作,不是为了在基因上复制人类,科学家们希望通过此举制造研究用的胚胎干细胞。虽然此前有过很多例克隆其他哺乳动物的试验,但这项工作首次证明了克隆技术是可应用在人类细胞上的。

  第4大突破

  美国和澳大利亚科学家制造出来了一种新型的冷凝物,一种超冷的气体能够滑入量子状态,该种状态中一组原子以一个超级原子的形式活动。这项突破之所以引人注意是因为它用到了费密子(一类拥有核心结构的原子,使它不易产生冷凝物。)

  第5大突破

  科学家发现“垃圾DNA”("junk" DNA)的重要作用。“垃圾DNA”是人类基因结构中已知基因之间的基本配对,扮演着重要角色。

  第6大突破

  天文学家发现了一对中子星的轨道相互交错,并且发出辐射光线。这两颗中子星都是脉冲星。天文学家希望通过对辐射光线的研究,能获知一颗中子星内部物质的密度大小。

  第7大突破

  负责研究世界各地现存的野生动物命运的自然科学家在2004年报告了一个坏消息:一项对两栖动物的调查显示,在已知5700个物种中,30%的物种面临着灭顶之灾。另外一项英国科学家的调查显示,蝴蝶、鸟类和很多在英国本土上生活着的物种在生存竞争中处于劣势。

  第8大突破

  水的新发现:尽管水是人们最为熟悉、最常见的已知物质,但是2004年,几组科 学家们在水分子如何聚合和电子及质子如何在水中溶解方面有了新发现。

  第9大突破

  世界各地公共机构与民间私营组织的合作,正改变着针对不发达国家的药物研制、试验和分配方式。据科学家统计,全世界有至少92家公私合营的机构组织在进行疟疾、肺结核或者艾滋病药物的研制。

  第10大突破

  科学家开发出一项能识别海水中或是埋在地下深处物种的基因的技术。上千种新基因因此被发现。通过给这些基因排列顺序,研究者希望能识别出新的物种,或是弄明白生物体是如何在恶劣或难以接近的条件下继续存活的。(任燕)





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